DC/DC converters are very widely used in power applications, that is, to transmit energy, typically from an energy source to a load. Such converters generally provide a galvanic isolation between upstream and downstream of the converter.
DC/DC converters can be found in many energy transfer and conversion application, be the final conversion AC/AC, AC/DC, DC/AC, or DC/DC. As an example, DC/DC power converters can be found in switched-mode power supplies, voltage inverters, voltage regulators, etc.
The transmission of control or low-power signals between upstream and downstream of a DC/DC converter most often requires either a second transformer, or optocoupler-type isolation elements.
Document US 2006/0120115 describes a power conversion system comprising an oscillating circuit, an oscillator control circuit to control oscillating circuit LC, a rectifying circuit coupled to oscillating circuit LC to supply an output DC, and a switching circuit to control the duty cycle of the oscillator control circuit to modulate the power in the oscillating circuit and the rectifying circuit.
Document US 2017/0358993 describes a galvanic isolation DC/DC converter with a bidirectional data transmission.
Document JP 2009 044837 describes a switched-mode power supply device to transmit signals by using a transformer to transmit the energy.